I agree, there will always be some clutter, barring a really drastic thing such as a fire and starting over from scratch, literally.

1. Don't beat yourself up
2.    ditto
3.    ditto
4.    ditto
5.    ditto:-)
6. It helps to have company while going through stuff, imo, just someone to visit, cheerlead, encourage, lift, shift, help

7. Start out small...one shelf, closet, counter, room, etc.

8. Do your research, as Maggie has done, and find places to which you may donate...it helps one to feel good that they are not just throwing stuff out...reusing, recycling, etc. give one a better sense of accomplishment, imo

9. Don't let go of anything which you may regret, i.e. something you have to spend money to replace, or something you feel you "should" have sold instead of given away or vice versa, sold something you feel would have been better going to someone as a gift

10. One of the best lessons I've received help with, in these threads, is not feeling duty bound to continue a loved one's colleciton/clutter/etc. i.e. it is OKAY to let go of your mom's tea towels, antique glass bottle,etc.:-)

Bonus Rule: HAVE FUN!